Reply to Re: [MYSQL Newbie Question] - Polling records from table with added index

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Posted by Wog George on 04/12/06 08:11

<endlesstide@gmail.com> wrote in message
news:1144814965.826469.104040@g10g2000cwb.googlegroups.com...
>
> My table looks like this...
>
> +------------+------------+------------+
> - Name - Value - Key -
> +------------+------------+------------+
> - Bill A. - 847 - 1 -
> +------------+------------+------------+
> - Mark B. - 4 - 2 -
> +------------+------------+------------+
> - Joe D - 63 - 3 -
> +------------+------------+------------+
> - April S - 103 - 4 -
> +------------+------------+------------+
> - Mark R. - 1387 - 5 -
> +------------+------------+------------+
> - Dave E. - 56 - 6 -
> +------------+------------+------------+
> And so on.... 1000 records like this.
>
> QUESTION: What is the most efficient query to select any 50 records,

Define "any 50 records". Does that mean a random sample of records? The
first 50? The last 50? The 50 top records that meet certain other
criteria? So far you've been told how to return records in a range and how
to limit the number of records returned. Are you sure everything's plugged
in??

> and sort them by Value ascending?

Um... ORDER BY VALUE ASC (although ASC is the default and doesn't need to be
specified. DESC is the opposite). You were told this already too. Did you
actually read any responses in the last thread you started on this topic?

> Someone said I needed to add a
> Index, which I did for the Value field. What does Cardinality mean?
>
On second thought, refer to my post about the Dummies Guide...

>
> I am on a learning curve to understand this - I appreciate real
> assistance to put together a query that works. Thank you for helping
> me advance my knowledge in this forum.
>

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